(1) Field of the Invention
This invention generally relates to a gage. More particularly, the invention relates to a feeler gage, which can effectively and economically measure the gap between a watertight hatch and its seat, when the assembly is subjected to submergence pressure.
(2) Description of the Prior Art
The current art for gages in connection with a submarines pressure hatch is normally designed with eight lugs, which extend beyond its gasket-sealing surface. The hatch is mated to a locking ring, which has similar lugs on its interior. When the locking ring is in one position, the hatch can open and close freely. However, if the locking ring rotates 22.5 degrees, the lugs on the locking ring cover the rings on the hatch and prevent it from opening. In addition, the locking ring itself is connected to its foundation by a threaded connection. Therefore, when the locking ring rotates, its moves axially. This results in the locking ring not only blocking the possibility of the hatch opening but it also pulls it firmly against its seat area. This is important to effect a tight seal when the assembly is subjected to sea pressure as well as holding the assembly securely, should it be subjected to a shock load.
However, whenever a submarine hatch assembly is subjected to submergence pressure it deflects in response to the loads induced by the pressure. Accordingly, there is a problem in the art wherein this deflection becomes greater as pressures increase. In addition, there is the potential for this deflection to actually lift the hatch off its gasket seat. If this occurs there is the possibility of the gasket extruding between the hatch and the seat area. If an excessive deflection occurs the assembly may leak. If the gasket extrudes between the hatch and its seat area then there is also the potential to pinch the gasket as the pressure causing component deflection, abates.
Therefore, it is very important to know how big a gap will result from pressurization so that a proper gasket design can be developed to match operating conditions. While this information can be obtained analytically, there is a need to validate the calculations prior to going to sea or implementing a design fix to a fleet problem. Presently, there is no method to measure the gap resulting from component deflections. This disclosure reveals an economical and effective method with the use of a feeler gage in order to determine this gap under either a test or an operating condition.
The following patents, for example, disclose various types of hatch covers, but do not disclose the use of an inexpensive feeler gage for determining a gap between a gasket seat and a hatch.
Specifically, Schoonman (U.S. Pat. No. 4,004,538) discloses a wave responsive hatch cover locking and sealing mechanism. In the mechanism, wave impact closes normally open contacts on a marine vessel hatch cover face to initiate or to increase fluid pressure within a collapsible hollow gasket interposed at the interface between a hatch cover and a deck hatchway to lock the hatch cover to the hatchway and to effect a watertight seal therebetween.
Rodgers et al. (U.S. Pat. No. 4,388,782) discloses a grinder for preparing circular seats behind elliptical handholes of marine boilers. An air motor, mounted within an expandable housing, drives a grinding wheel against the inside surface of the handhole. The housing is expanded to be secured in the elliptical handhole. The center of the motor orbits on a circle about the center of the housing so that a circular seat is formed about the inside edge of the elliptical handhole.
Leung (U.S. Pat. No. 4,466,551) discloses a releasable closure device adapted to provide sealing engagement between abutting surfaces by means of a rotatable locking ring comprising a plurality of locking lugs adapted to frictionally engage recessed locking channels disposed in the surfaces.
Wilger et al. (U.S. Pat. No. 4,534,135) discloses a machine provided for in-situ grinding of tapered lugs on a hatch, such as a hatch aboard a submarine. A base is provided and a device is attached to alternate lugs of the hatch for mounting the base across the hatch opening. An elongated plate is mounted at its center to the base for pivotal movement thereon. The pivotal plate has opposite ends wherein each end is extendable between a pair of alternate lugs, one of the lugs between one of the pair of lugs being a lug to be ground. A device is mounted on the base for oscillating the pivotal plate back and forth between the lugs of each pair of alternate lugs. A grinder is provided, and a device is utilized for mounting the grinder at one end of the pivotal plate for selectively engaging the grinder with or backing the grinder away from the lug to be ground. With this arrangement a lug can be ground by oscillating the pivotal plate and engaging the grinding means with the lug.
Duarte et al. (U.S. Pat. No. 5,562,065) discloses an elastomeric pump including a rigid outer housing defining an outer chamber and having a fluid inlet thereinto. The pump further includes an inner housing disposed within the outer housing. The inner housing is provided with rigid walls and first and second expandable members, the first expandable member having greater elasticity than the second expandable member, the rigid walls and expandable members defining an inner chamber. A fluid conduit extends from the inner chamber to the exterior of the outer housing. A rigid cage is fixed to the inner housing and is disposed over the first expandable member, and is configured to permit and limit expansion of the first expandable member.
It should be understood that the present invention would in fact enhance the functionality of the above patents by providing a feeler gage selectively inserted into an opening formed between a gasket seat and a seating surface of a hatch in a hatch-locking ring assembly as illustrated in the preferred embodiment of the present invention.